Answer:
-516
Step-by-step explanation:
Way #1
Step 1: Plug in x into the equation
-12(129) + 14(129) - 6(129)
-1548 + 1806 - 774
-516
Answer: -516
Way #2
Step 1: Or the other way is to simply the equation then plug x in.
-12(x) + 14(x) - 6(x)
-18x + 14x
-4x
Step 2: Then plug in x
-4(129)
-516
Answer: -516